如何NSObject和反射
NSObject 常用方法
如何判断 某个对象是否属于某个类或子类
-(BOOL)isKindOfClass:(Class)aClass
判断是否为aClass的实例(不包括aClass的子类)
-（BOOl）isMemberOfClass:(Class)aClass
判断是否实现了aProtocol协议
-(BOOL)conformToProtocol:(Protocol)aProtocol
判断这个类的对象是否拥有参数提供的方法
+（BOOL）instancesRespondToSelector:(SEL)aSelector
判断对象是否拥有参数提供的方法
-（BOOL）respondsToSelector:(SEL)aSelector
延迟调用参数提供的方法，方法所需参数用withobject 传入
-(void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay
//创建Person类
//继承Person的Student类
main.m
#import “Student.h”//enough
id stu=[[[Student alloc]init]autorelease];//Student *stu
//判断类型
//class 方法 返回一个指向结构体的指针
//the following code will judge this object of stu belong to the class of Student
if([stu isKindOfClass:[Student class]]) //Student can be replaced by Person
{
NSLog(@”stu belonged to Person or inherit from Person ”);
}
//only belong can’t inherit
BOOL result=[stu isMumberOfClass:[Student class]]; //Person –>no
//Student.h
@interface Student:Person
-(void)test;
-(void)test1:(int)a;
@end
Student.m
@implementation Student
-(void)test{
NSLog(@”call test”);
}
-(void)test1:(int)a{
NSLog(@”call test1,%i”,a);
}
@end
main.m
// call directly
[stu test];
[stu test1:10];
//indirect call
[stu performSelector:@selector(test:)];
[stu performSelector:@selector(test2:) withObject:];
//只能修改test2
test2:(NSString )str
//最多两个参数
[stu performSelector:@selector(test2:) withObject:@”abc”];
//performSelector在哪个线程调用，test2就在哪个线程
//延迟调用
[stu performSelector:@selector(test2:) withObject:@”abc” afterDelay:2];
//看不到效果，因为命令行项目这个函数一调用完，就是main的结尾，主程序关闭，定时器还有个屁用
反射：根据字符串来实例化一个对象
void reflect(){
NSString *str=@”Person”;
Class class=NSClassFromString(str);
//实例化
Person *person=[[class alloc]init];
NSLog(@”%@”,person);
[person release];
}